fix(world_state): restructure is-not-None guard for pylint 4.0.4 type narrowing

Pylint 4.0.4 does not narrow Optional types through early-return None guards
on instance attributes. Restructure the membership-test block inside an
 positive guard instead of using an
early-exit  pattern.

Semantically equivalent; resolves E1135/E1133 pylint errors:
  - world_state.py:295: E1135 unsupported-membership-test
  - world_state.py:298/301: E1133 not-an-iterable

Fixes #259

Author: nanookclaw

concordia/components/game_master/world_state.py

@@ -290,20 +290,18 @@ def _normalize_location(self, location: str) -> str:
     if not location:
       return ''
     location = location.strip().rstrip('.')
-    if self._valid_locations is None:
-      return location
-    valid_locations = self._valid_locations
-    assert valid_locations is not None  # Already checked above
-    if location in valid_locations:
-      return location
-    location_lower = location.lower()
-    for valid in valid_locations:
-      if valid.lower() == location_lower:
-        return valid
-    for valid in valid_locations:
-      if valid.lower() in location_lower:
-        return valid
-    return ''
+    if self._valid_locations is not None:
+      if location in self._valid_locations:
+        return location
+      location_lower = location.lower()
+      for valid in self._valid_locations:
+        if valid.lower() == location_lower:
+          return valid
+      for valid in self._valid_locations:
+        if valid.lower() in location_lower:
+          return valid
+      return ''
+    return location
 
   def post_act(
       self,